Hawley’s retainer & other URA. Function of URA. Arch development Arch length development Retainer . Arch Development. Schwartz appliances Component Expansion screw Clasp Labial bow Acrylic baseplate. I ndication Can be used for Class I or II cases, mixed or permanent dentition.
when there is an arch width deficiency in the
of a unilateral cross bite.
Simple to construct.
Fabricated in lab, resulting in a reduced chair time.
Can be removed for brushing, flossing and social reasons.
Acrylic palate is rigid → offers significant anchorage, maintains transverse expansion.
Allows more rapid vertical setting of teeth than vacuum-formed retainers, due to the lack of complete occlusal coverage.
Versatile → easily modified, and can be adjusted for finishing of treatments.
Durable → can last for several years
Success depends on patient compliance.
May be considered unaesthetic due to labial bow.
Speech might be impaired.
Wire crosses the occlusal plane.
Only tipping movements are possible.
Rotated teeth are extremely difficult to correct.
Patient with retroclined both upper central incisors.
Aim of treatment:
To procline the upper central incisors and prevent anterior crossbite
Active component: Double cantilever spring (Z-spring) on 11 and 21
Retentive components: Adams clasps on first premolars and first molars, labial bow
Anchorage: Adams clasps, baseplate
Baseplate: Acrylic (cold-cured polymethylmethacrylate), posterior bite planes
Example of simple URA